The oxidation behavior of a nickel-based superalloy was investigated from 650 to 1,000 °C for up to 1,000 h in air. Samples with thicknesses ranging from 20 to 500 µm were used to document the evolutions of microstructure and oxide scale. Oxidation products and subsurface evolution of the metal microstructure were characterized by XRD and EDS analyses. Local breakaway was observed after 600 h at 800 °C and after 100 h at 900 °C due to the full consumption of Cr from the alloy. Room temperature tensile tests were performed on aged and pre-oxidized specimens with thicknesses ranging from 20 µm to 500 µm, at 800 °C. The results were compared to tensile tests performed on the as-received metallurgical state. Both size effects due to sample thickness reduction and to sample thickness/pre-oxidation width ratio were examined onto the mechanical behavior. Interestingly, the formation of TCP phases, the oxide layer and the subsequent Cr-depleted subsurface region from either aging or oxidation treatments impairs the mechanical integrity. Bulk and subsurface regions are impacted, especially for tens-of-micrometer thin samples.

研究了镍基高温合金在空气中从 650 到 1,000 °C 氧化长达 1,000 小时的氧化行为。厚度范围为 20 至 500 µm 的样品用于记录微观结构和氧化皮的演变。通过 XRD 和 EDS 分析表征氧化产物和金属微观结构的亚表面演化。由于合金中的 Cr 完全消耗，在 800 °C 下 600 小时后和在 900 °C 下 100 小时后观察到局部脱离。在 800 °C 下对厚度范围为 20 µm 至 500 µm 的老化和预氧化样品进行室温拉伸试验。将结果与在原样冶金状态下进行的拉伸试验进行比较。由于样品厚度减少和样品厚度/预氧化宽度比导致的尺寸效应都在机械性能上进行了检查。有趣的是，TCP 相、氧化层和随后因老化或氧化处理而导致的 Cr 耗尽的亚表面区域的形成损害了机械完整性。大块和地下区域受到影响，特别是对于数十微米的薄样品。